Thanks Alban and Bigmac
It is not the MCU side causing problems it is the PC side! And there some improvements have to be done. I tried FTDI and some other USB/RS232 converters and the result is more or less the same. Since the latency of the USB-Bus is at least 1 ms the emulation of the 16C550 UART is not perfect! The MON08 interface software is also not working with the FIFO switched ON (on all my PSs!) and for me this is a sign, that the comunication protocol is not perfect. I tried to analyse (for hours in last two years) the timing on the hardware side, and there is all OK. I also have written a test programm to comunicate with the MCUs and this tests have all been OK.
So it would be on the CW side to add some delay between sending the byte and reading the two bytes (one ist the hardware echo and the other the MCU response). At least as an option, because the effect depends also on the MCU (ie. the AB32 works better than Q-family).
I would be glad, if it is possible to improove the CW, so students could use a cheep MON08-Interface to use the HC08 family even if they do not have a COM port on the Laptop.I also then could put my programmer with a USB/RS232 converter built in on my homepage. (www.systech-gmbh.ch)
Message Edited by peg on 2006-11-0502:12 PM